When Major Reed came to Pinar del Rio (July 21) I had, the day
before, established a separate yellow-fever hospital, under tents, attended
by some of the men who had already passed an attack and were thus
immune. The Major and I went over the ground very carefully, we
studied the sick report for two months back, fruitlessly trying to place
the blame upon the first case. I well remember how, as we stood in the
men's sleeping quarters, surrounded by a hundred beds, from several of
which fatal cases had been removed, we were struck by the fact that the
later occupants had not developed the disease. In connection with this,
and particularly interesting, was the case of a soldier prisoner who had
been confined to the guard-house since June 6; he showed the first
symptoms of yellow fever on the twelfth and died on the eighteenth;
none of the other eight prisoners in the same cell caught the infection,
though one of them continued to sleep in the same bunk previously
occupied by his dead comrade. More than this; the three men who
handled the clothing and washed the linen of those who had died during
the last month were still in perfect health. Here we seemed to be in the
presence of the same phenomenon remarked by Captain Stone in reference
to his case at Santa Clara, and before that by several investigators
of yellow-fever epidemics; the infection at a distance, the harmless condition
of bedding and clothing of the sick; the possibility that some insect
might be concerned in spreading the disease deeply impressed us
and Major Reed mentions the circumstance in his later writings. This
was really the first time that the mosquito transmission theory was seriously
considered by members of the board, and it was decided that, although
discredited by the repeated failure of its most ardent supporter,
Dr. Carlos J. Finlay, of Havana, to demonstrate it, the matter should
be taken up by the board and thoroughly sifted.
The removal of the troops out of Pinar del Rio was the means of at
once checking the propagation of the disease.
On the first day of August the board met and after due deliberation
determined to investigate mosquitoes in connection with the spread of
yellow fever. As Dr. Lazear was the only one of us who had had any
experience in mosquito work, Major Reed thought proper that he should
take charge of this part of the investigation in the beginning, while we,
Carroll and I, continued with the other work on hand, at the same time
gradually becoming familiar with the manipulations necessary in dealing
with the insects.
A visit was now made to Dr. Finlay, who, much elated at the news
that the board was about to investigate his pet theory, the transmission
of yellow fever from man to man by mosquitoes, very kindly explained to
us many points regarding the life of the one kind he thought most
guilty and ended by furnishing us with a number of eggs which, laid by
a female mosquito nearly a month before, had remained unhatched on
the inside of a half empty bowl of water in his library.
Much to our disappointment and regret, during the first week of
August, Major Reed was recalled to Washington that he might, in collaboration
with Drs. Vaughan and Shakespeare, complete the report upon
"Typhoid Fever in the Army.'' Thus we were deprived of his able
counsel during the first part of the mosquito research. Major Reed
was detained longer than he expected and could not return to Cuba until
early in October, several days after Lazear's death.
The mosquito eggs obtained from Dr. Finlay hatched out in due
time; the insects sent to Washington for their exact classification were
declared by Dr. L. O. Howard, entomologist to the Agricultural Department,
to be Culex fasciatus. Later, they
have been called
Stegomyia fasciatus and now go under
the name of Stegomyia
calopus (Aedes cal.).
Lazear applied some of these mosquitoes to cases of yellow fever at
"Las Animas'' Hospital, keeping them in separate glass tubes properly
labeled, and every thing connected with their bitings was carefully
recorded; the original batch soon died and the work was carried on with
subsequent generations from the same.
The lack of material at Quemados caused us to remove our field of
action to Havana, where cases of yellow fever continued to appear. We
met almost every day at "Las Animas'' Hospital, where Lazear was trying
to infect his mosquitoes, or now and then I performed autopsy upon
a case, and Carroll secured sufficient cultures to last him for several
days of bacteriological investigation.
Considering that, in case our surmise as to the insect's action should
prove to be correct, it was dangerous to introduce infected mosquitoes
amongst a population of 1,400 non-immunes at Camp Columbia, Dr.
Lazear thought best to keep his presumably infected insects in my
laboratory
at the Military Hospital No. 1, from where he carried them back
and forth to the patients who were periodically bitten.
Incidentally, after the mosquitoes fed upon the yellow fever patients,
they were applied, at intervals of two or three days, to whoever would
consent to run the risk of contracting yellow fever in this way; needless
to say, current opinion was against this probability and as time
passed and numerous individuals who had been bitten by insects which
had previously fed upon yellow fever blood remained unaffected, I must
confess that even the members of the board, who were rather sanguine
in their expectations, became somewhat discouraged and their faith in
success very much shaken.
No secret was made of our attempts to infect mosquitoes; in fact
many local physicians became intensely interested, and Lazear and his
tubes were the subject of much comment on the part of the Havana
doctors, who nearly twenty years before had watched and laughed at Dr.
Finlay, then bent apparently upon the same quest in which we were now
engaged. Dr. Finlay himself was somewhat chagrined when he learned
of our failure to infect any one with mosquitoes, but, like a true believer,
was inclined to attribute this negative result more to some defect in our
technique than to any flaw in his favorite theory.
Although the board had thought proper to run the same risks, if
any, as those who willingly and knowingly subjected themselves to the
bites of the supposedly infected insects, opportunity did not offer itself
readily, since Major Reed was away in Washington and Carroll, at
Camp Columbia, engrossed in his bacteriological investigations came to
Havana only when an autopsy was on hand or a particularly interesting
case came up for study. I was considered an immune, a fact that I
would not like to have tested, for though born in the island of Cuba,
I had practically lived all my life away from a yellow-fever zone; it was
therefore presumed that I ran no risk in allowing mosquitoes to bite
me, as I frequently did, just to feed them blood, whether they had previously
sucked from yellow-fever cases or not. And so, time passed and
several Americans and Spaniards had subjected themselves in a sporting
mood to be bitten by the infected (?) mosquitoes without causing any
untoward results, when Lazear applied to himself (August 16, 1900)
a mosquito which ten days before had fed upon a mild case of yellow
fever in the fifth day of his disease; the fact that no infection resulted,
for Lazear continued in excellent health for a space of time far beyond
the usual period of incubation, served to discredit the mosquito theory
in the opinion of the investigators to a degree almost beyond redemption,
and the most enthusiastic, Dr. Lazear himself, was almost ready to
"throw up the sponge.''
I had as laboratory attendant a young American, a private belonging
to the Hospital Corps of the Army, who more than once had bared his
arm to allow a weak mosquito a fair meal with which to regain its
apparently waning strength; Loud, for that was his name, derided the
idea that such a little beast could do so much harm as we seemed ready
to accuse it of, although he was familiar with the destruction caused by
bacteria, but then, he used to say, "bacterial work in armies of more
than a million bugs at the same time and no one would be d— fool
enough to let more than one or two gnats sting him at once.''
This state of things, the gradual loss of faith in the danger which
mosquitoes seemed to possess, led Dr. Lazear to relax a little and become
less scrupulous in his care of the insects, and often, after applying them
to patients, if pressed for time, he would take them away with him to
his laboratory at Columbia Barracks, where, the season being then quite
warm, they could be kept as comfortably as at the Military Hospital
laboratory. Thus it happened that on the twenty-seventh of August
he had spent the whole morning at "Las Animas'' Hospital getting his
mosquitoes to take yellow-fever blood: the procedure was very simple;
each insect was contained in a glass tube covered by a wad of cotton, the
same as is done with bacterial cultures. As the mouth of the tube is
turned downwards, the insect usually flies towards the bottom of the
tube (upwards), then the latter is uncovered rapidly and the open
mouth placed upon the forearm or the abdomen of the patient; after a
few moments the mosquito drops upon the skin and if hungry will
immediately start operations; when full, by gently shaking the tube, the
insect is made to fly upwards again and the cotton plug replaced without
difficulty. It so happened that this rather tedious work, on the
day above mentioned, lasted until nearly the noon hour, so that Lazear,
instead of leaving the tubes at the Military Hospital, took them all with
him to Camp Columbia: among them was one insect that for some reason
or other had failed to take blood when offered to it at "Las Animas''
Hospital.
This mosquito had been hatched in the laboratory and in due time
fed upon yellow-fever blood from a severe case on August 15, that is,
twelve days before, the patient then being in the second day of his illness;
also at three other times, six days, four days and two days before.
Of course, at the time, no particular attention had been drawn to this
insect, except that it refused to suck blood when tempted that morning.
After luncheon that day, as Carroll and Lazear were in the laboratory
attending to their respective work, the conversation turning upon
the mosquitoes and their apparent harmlessness, Lazear remarked how
one of them had failed to take blood, at which Carroll thought that he
might try to feed it, as otherwise it was liable to die before next day
(the insect seemed weak and tired); the tube was carefully held first by
Lazear and then by Carroll himself, for a considerable length of time,
upon his forearm, before the mosquito decided to introduce its proboscis.
This insect was again fed from a yellow fever case at "Las Animas''
Hospital on the twenty-ninth, two days later, Dr. Carroll being present,
though not feeling very well, as it was afterwards ascertained.
We three left the yellow-fever hospital together that afternoon; I
got down from the doherty-wagon where the road forks, going on to the
Military Hospital, while Carroll and Lazear continued on their way to
Camp Columbia. On the following day, Lazear telephoned to me in
the evening, to say that Carroll was down with a chill after a sea bath
taken at the beach, a mile and a half from Camp, and that they suspected
he had malaria; we therefore made an appointment to examine
his blood together the following morning.
When I reached Camp Columbia I found that Carroll had been
examining his own blood early that morning, not finding any malarial
parasites; he told me he thought he had "caught cold'' at the beach:
his suffused face, blood-shot eyes and general appearance, in spite of
his efforts at gaiety and unconcern, shocked me beyond words. The
possibility of his having yellow fever did not occur to him just then;
when it did, two days later, he declared he must have caught it at my
autopsy room in the Military Hospital, or at "Las Animas'' Hospital,
where he had been two days before taking sick. Although we insisted
that he should go to bed in his quarters, we could only get him
to rest upon a lounge, until the afternoon, when he felt too sick and had
to take to his bed.
Lazear and I were almost panic-stricken when we realized that Carroll
had yellow fever. We searched for all possibilities that might
throw the blame for his infection upon any other source than the mosquito
which bit him four days before; Lazear, poor fellow, in his desire
to exculpate himself, as he related to me the details of Carroll's mosquito
experiment, repeatedly mentioned the fact that he himself had
been bitten two weeks before without any effect therefrom and finally,
what seemed to relieve his mind to some extent, was the thought that
Carroll offered himself to feed the mosquito and that he held the tube
upon his own arm until the work was consummated.
I have mentioned before that, as Lazear and I, vaguely hoping to
find malarial parasites in Carroll's blood, sat looking into our microscopes
that morning, the idea that the mosquito was what brought him
down gradually took hold of our minds, but as our colleague had been exposed
to infection in other ways, by visiting the yellow fever hospital
"Las Animas,'' as well as the infected city of Havana, it was necessary
to subject that same mosquito to another test and hence the inoculation
of Private Dean, which is described in the opening chapter of this
history.
